Thermodynamic binding parameters of the p27-KID mutants.

In all the experiments above, the stoichiometry of binding (n) was determined to be one (1), with experimental error within 10%. The errors reported above are the standard deviations from the mean of three independent experiments.aCalculated with the equation ΔG = −RT ln(1/Kd ).bCalculated with the equation −TΔS = ΔG−ΔH.cThe c values (c = (Kd)−1 * [Cdk2/cyclin A]) for these p27-KID variants were >500 and the ΔG values reported here are taken as estimates of the upper limits of Kd. Ideal c values for accurate determination of Kd, have a range of 1 to 500. Specifically, the c values for the binding of p27-KIDwt and p27-KID−H to Cdk2/cyclin A complex are 2,212 and 1,698, respectively.